Magnetorheological fluids that comprise suspensions of ferromagnetic particles such as iron or iron alloys in a fluid medium have flow characteristics that can change by several orders of magnitude within milliseconds when subjected to a suitable magnetic field due to suspension of the particles. The ferromagnetic particles remain suspended under the influence of magnetic fields and applied forces. Such magnetorheological fluids have been found to have desirable electro-magnetomechanical interactive properties for advantageous use in a variety of magnetorheological (MR) damping devices, such brakes, clutches, mounts and dampers.
Regardless of the type of device, the magnetorheological fluid must be loaded or injected into the device during manufacture. Magnetorheological fluids tend to be costly; and, depending on what additives are used for different applications, the release of such fluids to the environment might be undesirable. Thus, it is desirable to dispense precisely the correct volume of fluid to the device, with no spillage.